Apparatus for balancing the axial thrust in single helical toothed wheel gearing



J. NIEDERHAUSER APPARATUS FOR BALANCING THE AXIAL THRUST IN SINGLE HELICAL TOOTHED WHEEL E R NG Filed April 19, 1923 Patented Aug. 4, 1925.

UNITED STATES PATENT OFFICE.

JAKOB NIEDERHAUSEER, F IBADEN, SWITZERLAND, ASSIGNOR TO AKTIENGESELL- SCHAFT BROWN, BOVERI AND CIE., OF BADEN, SWITZERLAND.

APPARATUS FOR BALANCING THE AXIAL THRUST IN SINGLE HELICAL TOOT HE WHEEL GEARING.

Application filed April 19,

the Axial Thrust in Single Helical Toothed Wheel Gearing, 'of which the following is a specification. I

The axial thrust in single helical toothed wheel gearing constructed hitherto has been taken either directly by the driving machine or by the driven machine, or by separate thrust bearings, so that finally the bearing casing has had to take the thrust. Thrust bearings occasion however a notinconsiderable increase in the cost of such caring.

In order to do away with t ese costly separate thrust bearings, recourse has been 1 had to the use of double helical toothed wheel gearing wherein each wheel is constructed as if it were combined of two helical half wheels arranged side by side with the teeth of each half-wheel inclined oppositely to the teeth of'the other half-wheel.

In such double helical wheels the unavoidable small errors of pitch which are never uniform in both halves of the wheels, cause corresponding differences in the peripheral forces, and consequently also in the axial thrusts of the two halves. of the ear, with the result that the wheels, in see ing to establish a balance between the two axial thrusts are continually impelled axially toand-fro, which is detrimental to the steady workingof .a gear of this nature.

It is now pro osed to revert to the use of the cheaper an more reliable single helical toothed wheels, and the present invention has for itsobject to provide improved apparatus by means of which the axial thrusts of single helical toothed wheels meshingc with one another are balanced directly, that is to'say, within the caring itself, taken as a self-contained mec anism, by means of separate rotary surfaces which are opposed to-one another and revolve together and serve as thrust surfaces for the revolving bodies.

The invention'will'now be more fully described with reference to the accompanying drawings which illustrate various constructional examples thereof.

Fig. 1 is a fragmentary side view of two 1923. Serial No. 633,318.

meshing single helical toothed wheels adapted to transmit power in one direction only andprovided with my improvements.

Fig. 2' is a similar view of a modified arrangement employed for transmitting power in .both directions of rotation.

Flgs. 3 and 4 are enlarged detail sectlonal views of other modified forms.

In Figure 1 a is a wheel driving a larger wheel I); c is a separate thrust surface pro-'.

vided on the wheel a, and (Z is a thrust surface provided on the wheel I). The. two separate thrust surfaces 0 and d co-operate together to take the respective axial thrusts of the two wheels. In working, the teeth will make a screwmg movement, until these thrust surfaces 0 and (Z bear against each other, whereupon the axial thrust of theone wheel will oppose directly the axial thrust of 'the other wheel, and thus the two axial thrusts will balance each other completely. These axial thrusts are consequently not transmitted in any way to the bearing casing, as is the case when thrust bearings are employed.- When a gear of this kind is to be employed for transmitting power in both directions of rotation, it is preferred to use the modified arrangement illustrated by way of example in Figure 2.- In this modified arrangement the thrust surfaces are shown formed on inter-engaging collars which have, in addition to the thrustsurfaces 0 and 0!, further surfaces e and f respectively which are intended to take the op ositely directed thrusts. It is to be un erstood that these surfaces 6 and may also be arranged in another manner, or example, on the opposite side of the pair of wheels.

When jolts occur in the working of such a gear the thrust rings or thrust collars are preferably made ,resilient, namely, these rings or collars are so constructed as to be resilient of themselves, or elastic intermediate members may-be arranged between them and their .respective whee s.

Although the running surfaces may be situated in one plane, yet, in order to get a better bearing film of. oil, it is preferred to make such running surfaces of convex shape, for instance, by making them of conical shape as shown in the drawings. The intar-engaging running or thrust surfaces of a pair of helical wheels willthen make contact with each other only along one line the contacting surfaces hem separated rom each other both before an after the line of contact. The distances between the working surfaces produce conditions similar to those existing 'in Michell or Kingsbury thrust block bearings, thus permitting high pressures between the surfaces of the pinion and the wheel. The convex running surfaces ensure in this manner a very intensified lubrication of the thrust zone because the lubricant is forced between them in the form of a wedge of oil.

The relative velocities of the parts of the thrust surfaces rolling over or sliding over one another depend upon the distance of these parts from the pitch circle.

In order to keep these velocities low, the thrust zone may be arranged close to the pitch circles, as is shown for instance, in Figure 3. V v

If, however, on the contrary, it is preferredto have a sliding motion, this can be attained by arranging these thrust surfaces outside; or inside the pitch circles, as is indi cated for instance, inQFigure 4. The same reference letters are; used in Figures 3 and fl, as in Figured.

For the Purpose of avoiding pit-ting in the zone o purely rolling friction, namely,

spective wheels and facing one another in a such a manner that axial end thrust due to rotation of the said pair of wheels is transferred to the engaging thrust surfaces.

2. Apparatus as 'claimed in claim 1, wherein one of the said thrust surfaces is formed on one end ofone of the said wheels.

3. Apparatus as claimed inclaim 1,

wherein the said thrust surfaces are located on bodies of revolution integral with their 1 said respective wheels.

4. Apparatus as claimed in claim. 1 wherein the said thrust surfaces are located on bodies of revolution integral with their said respective wheels and are formed by generatrices inclined to the axes of their respective helical wheels.

In testimony whereofI have signed my name to this s cification.

x JA OB NIEDERHAUSER. 

